A tennis supply store pays a wholersale $90 for a tennis racquet and sells it for $114. What is the markup rate?

First, what you want to do is subtract the price you sell it for by how much you got it for.

In this case, your equation would look like this: 114 - 90 = 24

You added $24 to the price that you bought. The amount added to the price would be $24

Then you would divide the amount added to the price by the amount it costed you to buy. It would end up as a decimal:

24 : 90 = 0.266 (infinite 6's)

Then with the decimal you got, you would multiply it by 100 to get the markup rate percentage.

0.266 * 100 = 26.66

The markup rate would be 26.66% (26.7 if you round).